1. Field of the Invention
The invention relates generally to alignment systems and, more particularly, to alignment systems that utilize electrical contact for precise alignment.
2. Background Information
Systems such as differential scanning calorimeters, or DSCs, for analyzing properties of materials, including phase changes during heating or cooling, and so forth, are complex, finely tuned instruments. The systems require precise movement of samples of the materials for analysis into and out of sample and control furnaces that are each small numbers of millimeters in diameter. The furnaces are sized to heat and cool rapidly, and thus, an analysis of a number of samples can be done relatively quickly by transporting the samples into and out of the respective furnaces. Typically, automated transport systems are used to move the samples.
The samples are held in pans, and each furnace is contoured to include a well that holds the sample pan during the analysis. Each pan, which is sized to fit within the furnace well, is thus an even smaller number of millimeters in diameter. The pans are, in turn, held in sample wells of a sample tray. The sample wells may, for example, be arranged in a grid such that the individual samples can be identified by their locations within the grid. The automated transport system moves a designated sample, i.e., a sample specified by its grid location, into the well of a designated furnace for analysis and thereafter returns the sample to the appropriate sample well. The transport system of interest includes a probe that regulates a vacuum to both pick up the sample pans from and deposit the sample pans in the sample and furnace wells. The transport system must operate with precision, to avoid damage to the sample pans, the furnaces and the probe through unintended contact.
The analytic results may also be adversely affected if the sample pan is imprecisely placed within a furnace well. If, for example, the sample pan is placed off-center and, in particular, if the pan touches the wall of the furnace, the heating or cooling may be affected. Indeed, certain samples may spill if the pans tip through contact with the furnace walls as the pans are lowered into the furnace wells, and thus adversely affect the analysis or even the operation of the furnace. Further, the pans may dent if they come in contact with the walls of the furnaces during transport, and the dented pans may alter the results of the analysis by, for example, creating relative hot or cold spots during heating.
The damage to the pans and/or furnaces may thus compromise the analysis of certain or all of the samples, requiring the repeating of the analysis with newly prepared samples. Further, the system may have to be idled for repair to the furnaces, the probe and/or other components of the transport system.
At start up and/or periodically the transport system must be aligned with the sample wells and the wells in the furnaces. To align the probe with the center of, for example, the well in one of the furnaces, known prior systems may require a skilled technician to manually direct the probe to the appropriate center position “by eye.” Alternatively, the systems may instead require the use of one or more strategically placed optical sensors to align the probe with the center position, based on, for example, reflections from the furnace well. Further, similar alignment is required with the sample tray wells, and so forth. The overall alignment is complex and may require a service engineer to periodically re-align system components to compensate for changes in the system mechanics as a result of the maneuvering of the probe by the technician and/or changes in the operations of the transport system components, such as the sensors, over time.